The Republic XP-72 was an American

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...

fighter-

interceptor Interceptor may refer to: Arts and entertainment Film and television * ''The Interceptor'', a British drama series on BBC One * Interceptor (game show), ''Interceptor'' (game show), a British television game show that ran during 1989 * Interc ...

developed by

Republic Aircraft A republic, based on the Latin phrase ''res publica'' ('public affair' or 'people's affair'), is a state in which political power rests with the public (people), typically through their representatives—in contrast to a monarchy. Although a ...

as a progression of the

P-47 Thunderbolt The Republic P-47 Thunderbolt is a World War II-era fighter aircraft produced by the American company Republic Aviation from 1941 through 1945. It was a successful high-altitude fighter, and it also served as the foremost American fighter-bombe ...

design. The XP-72 was designed around the

Pratt & Whitney R-4360 Wasp Major The Pratt & Whitney R-4360 Wasp Major is an American 28-cylinder four-row radial engine, radial reciprocating engine, piston aircraft engine designed and built during World War II. At , it is the largest-displacement aviation piston engine to be ...

28-cylinder

air-cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled ...

radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...

with a

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...

mounted behind the pilot and driven by an extension shaft from the engine. The armament consisted of six .50 caliber (12.7 mm) wing-mounted Browning AN/M2 machine guns and underwing racks for two 1,000 lb bombs; Alternative armament packages included two 37 mm M4 autocannons with four .50 caliber AN/M2s, or four M4 autocannons.

Design and development

The XP-72 development paralleled that of another Republic design, the XP-69 that was to be powered by an experimental 42-cylinder Wright R-2160 liquid-cooled inline radial engine mounted in the nose of the aircraft and driving

contra-rotating Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque. Examples include some aircraft propellers, r ...

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

s. The XP-69 was intended for high altitude operations and featured a pressurized cockpit and armament of two 37 mm cannon and four

50 caliber This is a list of firearm cartridges which have bullets in the to range. *''Length'' refers to the cartridge case Case or CASE may refer to: Instances * Instantiation (disambiguation), a realization of a concept, theme, or design * Specia ...

machine guns. As the XP-72 displayed greater promise than the XP-69, the XP-69 was canceled on 11 May 1943 and an order for two XP-72 prototypes was placed on 18 June 1943.

Operational history

The XP-72 flew for the first time on 2 February 1944, equipped with a four-bladed propeller. The second prototype was completed on 26 June 1944 and was equipped with an Aero-Products

contra-rotating propeller Aircraft equipped with contra-rotating propellers (CRP) coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single engine piston powered or turboprop engine to drive a pair of coaxial propellers i ...

. As the XP-72 displayed exceptional performance during flight tests, an order for 100 production aircraft was awarded. The order included an alternate armament configuration of four 37 mm cannon. By this time,

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

had progressed to where the need was for long-range escort fighters and not high-speed interceptors. Furthermore, the advent of the new

turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

-powered interceptors showed greater promise for the interceptor role. Thus, the production order for the P-72 was canceled.

Specifications (XP-72)

References

Notes

Citations

Bibliography

* Bodie, Warren. "The Whine of the Jug". ''Wings Magazine'' (Vol. 4, No. 4), August 1974, pp. 33–39. * Freeman, Roger A. ''Thunderbolt: A Documentary History of the Republic P-47''. London: Macdonald & Jane's (Publishers) Ltd., 1978. . * Green, William. ''War Planes of the Second World War - Fighters (Volume Four)''. London: Macdonald & Co.(Publishers) Ltd., 1961. . * Green, William and Gordon Swanborough. ''WW2 Aircraft Fact Files: US Army Air Force Fighters, Part 2''. London: Macdonald & Jane's (Publishers) Ltd., 1978. . * Jarski, Adam and Robert Michulec. ''P-47 Thunderbolt, P-35/P-43/XP-72 (Monografie Lotnicze 26)'' (in Polish). Gdynia: AJ-Press, 1996. .

External links

{{USAF fighters P-072 Republic P-72 Single-engined tractor aircraft Aircraft with contra-rotating propellers Low-wing aircraft Aircraft first flown in 1944 Aircraft with retractable conventional landing gear Cancelled military aircraft projects of the United States Single-engined piston aircraft